Today the prevalent bone conduction (bc) audiometric transducer
is the B-71 from Radioear Corporation, USA. This type of transducers
suffer from some severe limitations with regard to low frequency
response and distortion at high signal levels.
A new type of electro dynamic transducer for audiometric
investigations named Balanced Electromagnetic Separation Transducer
has been developed.
By using a balanced
with opposing air gaps,
the quadratic distortion
forces as well as the
always existing biasing
magnetic forces are
The advantages with this new design has been verified in a
number of laboratory tests on first series of prototypes.
Conclusively, from the laboratory
tests of the BEST performance compared with the conventional B-71
performance, it was found that:
lower distortion over the entire frequency range.
has a lower resonance frequency for a given counterweight mass.
is more efficient.
These results imply that bc tests can be conducted at lower
frequencies (down to 250Hz) and at higher levels than befor. In
general terms one can say that a more severe sensorineural hearing
losses can accurately be measured with the new transducer.